Above the forest line in the Southern Alps in the South Island of New Zealand are extensive areas partly covered in scrub and tussock, partly bare rocks and shingle, and mostly precipitous and difficult to traverse. This entire region is exposed to an unforgiving mountainous climate, snow and bleak winds in winter, mist and wind in summer. It is here, and in the upper margins of the beech forest, that the Kea, the world’s only mountain parrot, has evolved a level of intelligence that rivals that of the most sophisticated monkeys.

The Kea has become the stuff of legends, not only in Phillip Temple’s wonderful books but also in the minds of those who have come contact with this extraordinary bird, the clown of the mountains and, more darkly, the feathered wolf.

In the spring, the Kea digs up large mountain daisies in the alpine grasslands and searches at the edges of the snow mounds and around rocks for low growing plants and insects. In the summer they forage in the alpine shrubs for fruit, seeds and flowers. They feed from rata or mountain flax, lapping up the nectar and pollen and also catch numerous grasshoppers, beetles and grubs. The autumn they spend in the beech forests, eating shoots, leaves and nuts. But the winter is the cruelest time when many die of starvation. They seek animal fat and will tear open carcasses to consume meat and internal organs.

One small community of Keas haunts a desolate valley where the mountains run steeply down into the sea and where there are also colonies of sooty shearwaters, “mutton birds”. The mature birds are not to be seen during the day as they are out fishing but at night they return to their young in nest holes they have dug in the turf among the boulders. The squabs by the time they are four months old have been fed so well on the semi digested fish brought back by their parents that they are full of fat and weigh a couple of pounds. The locals used to harvest them in great numbers. So do the Keas.

A Kea stalks through the warren of shearwater nest holes, bending down every now and then, head cocked to listen. The shearwater chicks crouch silently in their burrows but occasionally they call. The Kea reacts swiftly and starts to dig. Using its beak like a mattock it tears away the earth around their burrow’s entrance and reaches inside. The mutton–bird is not entirely defenseless and may squirt fish oil into the Kea’s face. The beak that is so effective as a mattock now becomes a billhook and rips the young shearwater to pieces.

It is this murderous behaviour of the Kea and its propensity to attack merino sheep on high country stations which has made the bird so controversial and led to its persecution, the slaughter of as many as 150,000 of these birds over the past 130 years. For more than a century biologists have debated its character but more recent research throws new light on its extraordinary behaviour and history.

The ancestor of the three species of parrot in the genus Nestor, the Kea, its brown cousin the Kaka and their close relative the Norfolk Island Kaka, probably came from Australia. The ancestral Nestor may have arrived in New Zealand as many as 20 million years ago. With climate change and the separation into smaller islands in the early Pleistocene, two distinct populations developed. The population in the more benign north became Kakas specialising in exploiting fruit and nectar while the southern population living in the harsher environment where beech forest dominated, became Keas, developing the behavioural strategies and food preferences that would help them survive among the ice fields. There the Kea remained, an uncommon species of harsh and marginal habitats, no doubt following the great eagle and other predators for leftovers as well as plaguing the millions of petrels and shearwaters who bred on the mainland, until the first wave of humans arrived.

When forests were burned and the Moas were hunted to extinction and the Polynesian rat eliminated most of the shearwaters from the mainland, Keas shifted to other sources of food. As dietary generalists they were relatively resistant to the environmental changes that forced many other birds into extinction.

The second wave of human settlement brought a bonus to the Kea. While the Kaka declined as the bush was felled and burned, the Kea population exploded with the advent of European settlement of the high country during 1840s and 50s. When sheep began to die in snowfields, Keas rediscovered a lucrative livelihood as scavengers and even attacked live sheep. Numbers increased dramatically. This ability to tolerate massive environmental change and make the most of new opportunities sets the Kea apart from nearly every other island species.

This ability to adapt and survive arises out of the Kea’s social organisation and its propensity to play. Like coyotes, crows and humans, Keas are “open–programme” animals with an unusual ability to learn and to create new solutions to whatever problems they encounter. Exploring and manipulating the objects in their environment, Keas were selected primarily for individual rather than social learning. In essence keas were selected to play, since only through play could the requisite level of flexibility be achieved. Its boldness, destructiveness and curiosity are aspects of play, scientists say.

The Kea was not fully protected until 1986 when high country farmers were persuaded to give up their legal right to shoot Keas in exchange for an undertaking by the government agencies to investigate all reports of Kea attacks on sheep and to remove all problem birds. Ski-field operators were encouraged to make their equipment proof against the Kea’s powerful beak. In this way we are learning to live with and to give room to our wildlife.